Commit 092b50ba authored by Naoya Horiguchi's avatar Naoya Horiguchi Committed by Linus Torvalds
Browse files

pagemap: introduce data structure for pagemap entry 



Currently a local variable of pagemap entry in pagemap_pte_range() is
named pfn and typed with u64, but it's not correct (pfn should be unsigned
long.)

This patch introduces special type for pagemap entries and replaces code
with it.

Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 807f0ccf

fs/proc/task_mmu.c

+38 −31
Original line number Diff line number Diff line
@@ -594,9 +594,13 @@ const struct file_operations proc_clear_refs_operations = { 
	.llseek		= noop_llseek,

};



typedef struct {

	u64 pme;

} pagemap_entry_t;



struct pagemapread {

	int pos, len;

	u64 *buffer;

	pagemap_entry_t *buffer;

};



#define PAGEMAP_WALK_SIZE	(PMD_SIZE)
@@ -619,10 +623,15 @@ struct pagemapread { 
#define PM_NOT_PRESENT      PM_PSHIFT(PAGE_SHIFT)

#define PM_END_OF_BUFFER    1



static int add_to_pagemap(unsigned long addr, u64 pfn,

static inline pagemap_entry_t make_pme(u64 val)

{

	return (pagemap_entry_t) { .pme = val };

}



static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,

			  struct pagemapread *pm)

{

	pm->buffer[pm->pos++] = pfn;

	pm->buffer[pm->pos++] = *pme;

	if (pm->pos >= pm->len)

		return PM_END_OF_BUFFER;

	return 0;
@@ -634,8 +643,10 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end, 
	struct pagemapread *pm = walk->private;

	unsigned long addr;

	int err = 0;

	pagemap_entry_t pme = make_pme(PM_NOT_PRESENT);



	for (addr = start; addr < end; addr += PAGE_SIZE) {

		err = add_to_pagemap(addr, PM_NOT_PRESENT, pm);

		err = add_to_pagemap(addr, &pme, pm);

		if (err)

			break;

	}
@@ -648,36 +659,33 @@ static u64 swap_pte_to_pagemap_entry(pte_t pte) 
	return swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT);

}



static u64 pte_to_pagemap_entry(pte_t pte)

static void pte_to_pagemap_entry(pagemap_entry_t *pme, pte_t pte)

{

	u64 pme = 0;

	if (is_swap_pte(pte))

		pme = PM_PFRAME(swap_pte_to_pagemap_entry(pte))

			| PM_PSHIFT(PAGE_SHIFT) | PM_SWAP;

		*pme = make_pme(PM_PFRAME(swap_pte_to_pagemap_entry(pte))

				| PM_PSHIFT(PAGE_SHIFT) | PM_SWAP);

	else if (pte_present(pte))

		pme = PM_PFRAME(pte_pfn(pte))

			| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT;

	return pme;

		*pme = make_pme(PM_PFRAME(pte_pfn(pte))

				| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);

}



#ifdef CONFIG_TRANSPARENT_HUGEPAGE

static u64 thp_pmd_to_pagemap_entry(pmd_t pmd, int offset)

static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme,

					pmd_t pmd, int offset)

{

	u64 pme = 0;

	/*

	 * Currently pmd for thp is always present because thp can not be

	 * swapped-out, migrated, or HWPOISONed (split in such cases instead.)

	 * This if-check is just to prepare for future implementation.

	 */

	if (pmd_present(pmd))

		pme = PM_PFRAME(pmd_pfn(pmd) + offset)

			| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT;

	return pme;

		*pme = make_pme(PM_PFRAME(pmd_pfn(pmd) + offset)

				| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);

}

#else

static inline u64 thp_pmd_to_pagemap_entry(pmd_t pmd, int offset)

static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme,

						pmd_t pmd, int offset)

{

	return 0;

}

#endif
@@ -688,7 +696,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, 
	struct pagemapread *pm = walk->private;

	pte_t *pte;

	int err = 0;

	u64 pfn = PM_NOT_PRESENT;

	pagemap_entry_t pme = make_pme(PM_NOT_PRESENT);



	if (pmd_trans_unstable(pmd))

		return 0;
@@ -702,8 +710,8 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, 


			offset = (addr & ~PAGEMAP_WALK_MASK) >>

					PAGE_SHIFT;

			pfn = thp_pmd_to_pagemap_entry(*pmd, offset);

			err = add_to_pagemap(addr, pfn, pm);

			thp_pmd_to_pagemap_entry(&pme, *pmd, offset);

			err = add_to_pagemap(addr, &pme, pm);

			if (err)

				break;

		}
@@ -723,11 +731,11 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, 
		if (vma && (vma->vm_start <= addr) &&

		    !is_vm_hugetlb_page(vma)) {

			pte = pte_offset_map(pmd, addr);

			pfn = pte_to_pagemap_entry(*pte);

			pte_to_pagemap_entry(&pme, *pte);

			/* unmap before userspace copy */

			pte_unmap(pte);

		}

		err = add_to_pagemap(addr, pfn, pm);

		err = add_to_pagemap(addr, &pme, pm);

		if (err)

			return err;

	}
@@ -738,13 +746,12 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, 
}



#ifdef CONFIG_HUGETLB_PAGE

static u64 huge_pte_to_pagemap_entry(pte_t pte, int offset)

static void huge_pte_to_pagemap_entry(pagemap_entry_t *pme,

					pte_t pte, int offset)

{

	u64 pme = 0;

	if (pte_present(pte))

		pme = PM_PFRAME(pte_pfn(pte) + offset)

			| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT;

	return pme;

		*pme = make_pme(PM_PFRAME(pte_pfn(pte) + offset)

				| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);

}



/* This function walks within one hugetlb entry in the single call */
@@ -754,12 +761,12 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask, 
{

	struct pagemapread *pm = walk->private;

	int err = 0;

	u64 pfn;

	pagemap_entry_t pme = make_pme(PM_NOT_PRESENT);



	for (; addr != end; addr += PAGE_SIZE) {

		int offset = (addr & ~hmask) >> PAGE_SHIFT;

		pfn = huge_pte_to_pagemap_entry(*pte, offset);

		err = add_to_pagemap(addr, pfn, pm);

		huge_pte_to_pagemap_entry(&pme, *pte, offset);

		err = add_to_pagemap(addr, &pme, pm);

		if (err)

			return err;

	}

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